CN107075925B

CN107075925B - Multipurpose double-abutting-part sealing connection

Info

Publication number: CN107075925B
Application number: CN201580055764.3A
Authority: CN
Inventors: R·布朗利; F·卡罗
Original assignee: Vallourec Oil and Gas France SAS
Current assignee: Vallourec Oil and Gas France SAS
Priority date: 2014-10-16
Filing date: 2015-10-14
Publication date: 2020-03-31
Anticipated expiration: 2035-10-14
Also published as: EA031062B1; AU2015332753A1; MX2017004917A; EP3207208A1; FR3027338A1; CA2962539A1; EA201790605A1; US10563466B2; JP2017532512A; CN107075925A; US20170298698A1; BR112017007196B1; BR112017007196A2; AR102282A1; FR3027338B1; WO2016059103A1; EP3207208B1; AU2015332753B2

Abstract

A threaded connection (30) with a double abutment shoulder comprising a first tubular component fitted on a second tubular component, the tubular components being intended for exploration or operation of hydrocarbon wells,. the first tubular component (C1) has an outer abutment (BE), an unthreaded terminal end portion (PT1) extending via a male threaded connection portion (PC1) defining an inner abutment (BI) at its axial ends; -the second tubular part (C2) comprises a female end defining, at a free end, a bearing Surface (SA) against the outer abutment and terminating in an inner shoulder (EI) against the inner abutment, a female threaded connection portion (PC2) being fitted with the male threaded connection portion, an unthreaded initial portion (PT2) connecting the female threaded connection portion to the inner shoulder, the threaded connection comprising a maximum radial interference between the male threaded connection portion and the inner abutment forming in part a sealing surface, this maximum radial interference being located at a non-zero distance (d5) from the inner abutment, this distance being at least greater than half the axial distance (d1) of said terminal portion.

Description

Multipurpose double-abutting-part sealing connection

Technical Field

The present invention relates to a quality threaded tubular connection, in particular for connecting steel pipes, such as tubular components used in oil or gas fields. In particular, the invention is applicable to components for drilling and components used under conditions of high internal and external pressure. These components must withstand tensile and compressive loads, such as those encountered during operations for hydraulic fracturing of rock, cementing of wells, or integrity testing on wells; these operations are even more dangerous when carried out offshore.

There is a need for a connection that can be used in drilling and that ensures a seal.

The invention is also suitable for use as an offshore string connecting a subsea wellhead to a drilling platform from a platform known as an "offshore" platform and subjected to large fatigue stresses as well as bending, tensile and torsional stresses due to the action of sea waves, tides and currents. These offshore strings, referred to as "drill string risers," may be used to convey the tools and instrumentation necessary to monitor the operating parameters of the well ready for production (referred to in this case as "workover risers") as well as the tools and instrumentation necessary for the first step in well production (referred to in this case as "early production risers").

These strings are frequently assembled and disassembled and require connections that maintain their integrity during use.

Due to the large pressure variations that may exist between the inside and the outside of the column, there is a need to improve the sealing of the connection formed between these pipes. There is also an economic need for connections that allow versatile pipes to be used for carrying out various activities at the production site, in particular for drilling and cementing.

Background

In the prior art, double abutment threaded connections having an internal abutment and an external abutment (i.e. upstream and downstream of the threaded portion) are generally used for the drilling step. In particular, documents US-5908212, WO-2005/095840 and WO-2006/092649 disclose various threaded connection solutions provided with double abutments of this type, and each represents a compromise in the design of the threading of the threaded portion, the inclination of the threaded portion, the distribution of the axial load on the abutments or the makeup torque required for this type of connection-all parameters that practically define the implementation conditions of the threaded connection solution.

Furthermore, document US6511102 describes a connection dedicated to fixed strings, for connecting a subsea wellhead to an offshore oil platform. Document US6511102 discloses a double-abutment threaded connection provided with a thread, which can be used to increase its capacity under tension and has a double sealing surface. While a threaded connection is satisfactory for use in a string of tubulars intended for a particular job in a well or requiring the insertion of lightweight instruments and accessories to perform production testing, the connection has not been validated for use with operating conditions of internal pressures above 15000psi and external pressures no higher than 10000 psi. Furthermore, this type of connection has a small abutment surface area, which prevents its use in drilling operations.

Thus, there is a need for an improved double abutment connection which can be used to obtain high assembly torques and which has multiple uses in use, which can be used for at least one other operation in the first step of production in addition to drilling, selected from cementing, performing well sealing and integrity tests or in performing tests on wellhead devices. Cementing and performing sealing tests expose the string to very high internal pressures. Cementing operations are intended to fix in place a casing lowered into the well, or to temporarily close the well entrance, in view of future work or at the end of the well's working period.

In particular, there is a need for a connection that can be used for drilling in unconventional pressure conditions (e.g., low pressure conditions within a tubular string).

Disclosure of Invention

The present invention aims to solve the problem posed by providing a threaded connection with a double abutment shoulder, comprising a first tubular component fitted on a second tubular component, the first and second tubular components being intended for exploration or operation of hydrocarbon wells;

-the first substantially cylindrical tubular component has an axis of rotation and comprises a protruding end comprising an external abutment, a protruding threaded connection portion, an unthreaded protruding base, the protruding threaded connection portion extending via an unthreaded terminal end portion defining an internal abutment at an axial end thereof, the unthreaded protruding base being defined between the external abutment and the protruding threaded connection portion;

the second substantially cylindrical tubular part comprises a female end defining, at a free end, a bearing surface pressed against the external abutment, this female end having, on its internal surface, a female threaded connection portion and ending in an internal shoulder pressed against the internal abutment, the female threaded connection portion being fitted with the male threaded connection portion, an unthreaded start portion connecting the female threaded connection portion to the internal shoulder, an unthreaded female base being defined between the female threaded connection portion and the bearing surface,

said connection comprises a maximum radial interference forming locally a sealing surface, located between said male threaded connection portion and said inner abutment or said outer abutment, this maximum radial interference being located at a non-zero distance from said inner abutment and said outer abutment, respectively, this distance being at least greater than 50% of the minimum between the axial distance of said terminal portion and the axial distance of said initial portion.

As an example, this maximum radial interference may be located between the male threaded connection portion and the inboard abutment.

In particular, a continuous interference is formed from the inner abutment to the maximum radial interference to prevent the formation of volumes capable of risking the trapping of gases, which would create operational risks during operation for the connection.

More particularly, the maximum radial interference can be obtained by the interaction between the tip of an annular portion, located on one of said terminal portion or said initial portion, and a tapered portion, located on the other of said terminal portion or said initial portion.

As an example, the annular portion may be located on the initiation portion and the tapered portion may be located on a convex inclined region of the tip portion.

In particular, the radius of curvature of the annular portion may be greater than 50mm, for example of the order of 300 mm.

In particular, the tip of the annular portion is located at an axial distance with respect to the inner abutment, which can be located between 60% and 90%, in particular between 70% and 80%, of the axial distance of the initial portion with respect to the inner shoulder.

Advantageously, the position of compression of the tip of the annular portion on the convex inclined area may be located at an axial distance with respect to the inner abutment lying between the range 5mm and 25mm, preferably between the range 10mm and 20mm, in particular about 18 mm.

As an example, said maximum radial interference is located at a radial distance from the start of said threaded connection, this radial distance being for example in the range between 2mm and 5 mm.

In particular, the thread pitch (Y) of these respective male and female threaded connection portions relative to the axis of the threaded connection may be in the range of 8.33cm/m (1.0 inch/foot) to 10cm/m (1.2 inch/foot).

Finally, the invention also relates to a method for coupling a threaded connection according to the invention, in which method the connection develops a nominal makeup torque of more than 22250N/m when the threaded connection of the invention has an external diameter of more than 13.02cm (51/8 inches) and an internal diameter of more than 7.18cm (27/8 inches).

In particular, such a coupling method may be characterized such that when the threaded connection of the present invention has an outside diameter greater than 20.32cm (8 inches) and an inside diameter greater than 13cm (5.119 inches), the nominal makeup torque may be greater than 70000N/m.

The inventive connections may be used to achieve a nominal make-up torque higher than those produced according to the American Petroleum Institute (API) standard. The connection of the present invention can be used to achieve at least 90% of the nominal make-up torque of prior art connections that do not have an annular sealing system obtained by radial metal-to-metal interference.

Drawings

The invention will be better understood from the following description and the accompanying drawings. The drawings are presented by way of indication only and are not limiting of the invention in any way. In the drawings:

FIG. 1 illustrates an offshore oil platform showing the use of a string of tubular members according to the present invention;

fig. 2 is a detailed longitudinal sectional view along the insertion frame a of fig. 1 of the double abutment threaded connection according to the invention;

FIG. 3 is a detailed longitudinal cross-sectional view of the insert frame B of FIG. 2, wherein the threaded male and female elements of the invention are shown separated from each other;

FIG. 4 is a detailed longitudinal cross-sectional view of the insert box C1 of FIG. 3, wherein FIG. 4 shows the sealing portion located in the unthreaded end portion of the male member of the threaded connection of the present invention;

FIG. 5 is a detailed longitudinal cross-sectional view of the insert box C2 of FIG. 3, wherein FIG. 5 shows the sealing portion located in the unthreaded start portion of the female element of the threaded connection according to the present invention;

FIG. 6 is a longitudinal cross-sectional view of a threaded connection in engagement with a threaded connection according to the present invention;

fig. 7 shows the variation of the elastic deformation of the abutment and of the maximum metal-metal radial interference area during the assembly of the connection according to the invention;

fig. 8a, 8b and 8c show detailed cross-sectional views of the portions between the threaded connection portion and the internal abutment which are in engagement when engagement is started between the threaded connection portion and the internal abutment during makeup of the threaded connection of the invention; fig. 8c shows the connection in its final position after assembly.

Detailed Description

Fig. 1 shows an offshore drilling installation 10 in which the invention can be used to advantage. In the illustrated example, the facility 10 includes an offshore platform 12 that floats on the sea. The platform 12 includes a drilling rig 14, the drilling rig 14 being equipped with a rotary table 16 and various fittings for gripping and manipulating various elements used in the construction and operation of the well. The platform 12 is thus located directly above a subsea well 20 drilled into the seabed F. Subsea well 20 is here shown enclosed within 21. The installation 10 comprises a pipe string 22 (termed a riser) which connects the floating platform 12 and a wellhead 23 by forming a pipe exposed to the ocean currents and maintaining a protected inner space for the well forming steps, in particular for drilling.

In the example shown in FIG. 1, a drill string 24 is movably disposed in the tubular string 22. The drill string 24 comprises a plurality of tubular components connected end to end via their ends. The tubular member of the present invention is made of steel.

According to the invention, the tubular components of the drill string shown are formed into an end-to-end assembly using a threaded connection 30 according to the invention. The assembly is carried out between a male threaded connection, known as "pin", and a female threaded connection, known as "box".

A threaded pipe connection in accordance with optimized fitting specifications ensures optimized mechanical strength in the resulting connection, for example with regard to tensile loads, at the same time with regard to protection against accidental tripping during service and with regard to optimized sealing performance.

In detail, as shown in fig. 2, the threaded connection 30 of the present invention comprises a first tubular member C1 and a second tubular member C2.

The first tubular component C1 comprises a first body 3, said first body 3 being substantially cylindrical with an axis of rotation X. The first body 3 is ring welded (e.g. by friction welding) to the second tubular body 10. In particular, the first body 3 may have an outer diameter P_ODAnd its inner diameter P_IDAs defined. The wall thickness of the first body 3 is greater in a part close to the welding zone 6 than in the remaining part of the first body. The wall thickness can be increased by a larger outer diameter PU_ODOr smaller inner diameter PU_IDBut is obtained locally. In particular, the outer diameter P of the first body 3_ODIn the range of 7.30cm (27/8 inches) to 22.86cm (9 inches), preferably between 10.16cm (4 inches) to 19.37cm (75/8 inches), including 14.92cm (57/8 inches).

In order to be associable with the second tubular component C2, the second body 10 has a connecting element 11, said connecting element 11 being able to cooperate with a complementary connecting element 13 carried by the second tubular component C2. Engaging connecting element 11 and connecting element 13 forms threaded connection 30 of the present invention. In the example shown in fig. 2, the connecting element 11 is a male element and the connecting element 13 is a female element.

In particular, the second body 10, known as a drill collar, may be formed with its maximum outer diameter TJ_ODAnd its inner diameter TJ_IDSaid second body 10 is defined as being substantially cylindrical with a rotation axis X. In particular, the maximum outer diameter TJ of the second body 10_ODIs in the range of 12.06cm (43/4 inches) to 22.22cm (83/4 inches). The outer diameter of the second body 10 is larger than the outer diameter of the first body 3. In particular, the maximum internal diameter TJ of the second body 10_IDIn the range of 6.19cm (27/16 inches) to 14.29cm (55/8 inches), and even as high as 15.87cm (61/4 inches).

The second body 10 is preferably made of steel having a grade on the order of 130ksi and a yield strength between 120000psi and 140000 psi; the second body 10 may be selected from higher grades of steel of about 140ksi, 150ksi and 165ksi, as well as from low grade steels, such as about 80ksi or 95ksi or even 110 ksi.

The second tubular member C2 includes a first body 3' and a third body 12. The first body 3' has substantially the same structural and dimensional features as the first body 3. The first body 3' is also welded annularly at 6 to the third body 12, respectively. The third body 12 has the above-mentioned complementary connecting element 13.

The connection 30 is formed such that the outer and inner diameters of the second and

third bodies

10, 12 have the same maximum outer diameter and the same inner diameter at least in the vicinity of the connection region thereof as indicated by the insertion frame B.

Advantageously, the third body 12 is made of the same grade of steel as the second body 10.

The profiles of the connecting

elements

11 and 13 are preferably obtained by machining. In particular, chemical or mechanical surface treatments can be carried out on these machined parts. The treatment may also be a phosphatization treatment by using manganese or zinc or even a frosting treatment. After the surface treatment, a storage or mounting grease may be deposited on the

connection elements

11 and 13.

The connection 30 has a double abutment on the inside and outside.

The second body 10 has an outer abutment BE at its outer periphery. The outer abutment BE has the shape of a flat annular recess. The plane of this recess forms an acute or right angle (in particular 90 ° in fig. 3) with the axis X.

The outside abutment BE is connected to the male threaded connecting portion PC1 via the base B1. Male base B1 is unthreaded; the projecting base B1 extends along the axis X and has an annular surface at its periphery that is generally parallel to the axis X. The basic shape of the connecting portion PC1 is an external truncated cone, the diameter of which decreases with increasing distance from the base B1. The connection portion PC1 carries threads on its outer periphery. The connection part PC1 extends via an unthreaded end part PT 1. The terminal portion PT1 is connected to a transverse surface forming an inboard abutment BI at the free axial end of the terminal portion PT 1.

The inner abutment BI presents a flat annular surface. The plane of the surface forms an acute or right angle (in particular 90 in fig. 3) with the axis X. The inboard abutment BI is connected to the inner circumference defined by the body C1.

Wherein the inner diameter TJ in the region of the outer periphery of the body C1 defined by the outside abutment BE, the projecting base B1, the connecting portion PC1 and the tip end portion PT1_IDIs substantially constant.

In practice, when a connection is made between the two bodies C1 and C2, the respective axes of rotation of the bodies substantially coincide.

The third body 12 extends along an axis X. Said third body 12 having a circular cross-section, the maximum outer diameter of the third body 12 being, for example, substantially equal to the maximum outer diameter TJ_OD. When forming the connection 30 of the invention, the free axial end of the third body 12 oriented towards the first body 10 defines a bearing surface SA.

The support surface SA is a flat annular surface. The plane of the surface forms an acute or right angle (in particular 90 in fig. 3) with the axis X. The bearing surface SA is connected to the outer periphery of the third body 12. The bearing surface SA is also connected to the inner periphery of this hollow third body 12, in particular to the concave base B2 thereof. Concave base B2 is unthreaded; concave base B2 defines a cylindrical inner periphery, and the axis of the cylindrical inner periphery is parallel to axis X.

Concave base B2 connects bearing surface SA to concave threaded connection PC 2. Connection portion PC2 has a generally tapered shape around its inner periphery and has threads that can mate with the threads of male connection portion PC 1.

To optimize the dimensions of the contact surface defined between the bearing surface SA and the outboard abutment BE, the concave base B2 may BE inclined while the convex base B1 remains cylindrical.

The concave connecting portion PC2 extends inside via the start portion PT 2. The initial portion PT2 extends substantially along the axis X. The initial portion PT2 connects to an internal shoulder EI defined transversely to the axis X. The inclination of the inboard shoulder EI with respect to the axis X is substantially the same as the inclination of the inboard abutment BI with respect to the axis X. As can be seen in fig. 3, the inside shoulder EI defines a flat annular surface in a plane perpendicular to the axis X.

When the connection 30 is made, the bearing surface SA is in contact with the outboard abutment BE over at least a portion of its surface, and similarly the inboard abutment BI is in contact with the inboard shoulder EI over at least a portion of its surface.

The connection portion of threaded connection 30 formed by the interaction between the threads carried by male threaded connection portion PC1 and the threads carried by female threaded connection portion PC2 is shown in greater detail in fig. 6.

In particular, the inclination of the thread Y with respect to the axis X of the connection ranges between 8.33cm/m (1.0 inch/foot) and 10cm/m (1.2 inch/foot). Preferably, the threads may be flank-flank interference. As an example, the thread of male connection portion PC1 and the thread of corresponding female thread portion PC2 may have stabbing flanks (stabbing flanks) 14 and load flanks 15, the stabbing flanks 14 being angled between 35 ° and 42 ° (particularly about 40 °) relative to the thread axis Y, the load flanks 15 being angled between 25 ° and 34 ° (particularly about 30 °) relative to the thread axis Y. As one example, the base 16 of the thread may have the shape of a portion of an ellipse. Advantageously, the direction of inclination of the crest 17 of the thread is opposite to the direction of inclination of the base of the thread.

In particular, the connection portion may comprise a thread, as described for example in patent US 5908212. The threads may comprise tapered or trapezoidal threads. The connecting portion may comprise incomplete thread regions having the same thread form upstream and downstream of the complete thread region.

The threaded connection 30 of the invention comprises a metal-to-metal seal formed between the terminal portion PT1 and the starting portion PT2, and between an internal abutment BI obtained by pressing engagement of the internal abutment BI against the internal shoulder EI and a connection portion obtained by engaging the male threaded connection portion PC1 with the female threaded connection portion PC 2. This example will be described in more detail below.

Alternatively, however, in embodiments that are not provided in detail and can BE derived symmetrically to the embodiments defined above, a metal-to-metal seal may BE formed at the base B1 and the base B2, i.e. between the outboard abutment BE and the connecting portion.

This metal-to-metal seal is achieved by locally forming an annular interference zone, in particular by radial interference.

The end portion PT1 is connected to the inboard abutment BI via the rounded portion 40. The rounded portion 40 is, for example, a circular portion having a radius of curvature in the range of 1mm to 1.6mm (preferably, about 1.3mm is selected). Starting from the rounded portion 40, the periphery of the end portion PT1 has an area 41 inclined with respect to the axis X. In particular, the inclination is greater than the inclination of the thread axis Y with respect to the axis X. In particular, the convex inclined area 41 forms an angle with the axis X lying between a range of 5 ° and 15 °, for example of the order of 7.125 ° (taper 1/4). In this example, the convex inclined region 41 is continuously inclined at the same inclination. The convex inclined region 41 defines a tapered portion.

The terminal portion PT1 extends parallel to the axis X along an axial distance d1 between the internal abutment BI and the threaded connection PC 1. The distance d1 may be in the range of 5mm to 50 mm.

Preferably, the axial distance d3 is defined from the fillet angle 40, and the convex inclined region 41 extends along the axial distance d3 with the same inclination. The axial distance d3 represents more than 50%, preferably more than 70%, of the axial length d 1.

The start portion PT2 is connected to the inboard shoulder EI via a radiused portion 43. The round portion 43 is, for example, a curved portion having a radius of curvature in the range of 1mm to 1.6mm (preferably, about 1.3 mm). Starting from the rounded portion 43, the initial portion PT2 comprises, in succession, a concave area 42 and an annular portion 45, said concave area 42 being inclined with respect to the axis X.

The concave sloped region 42 defines a tapered surface. In particular, the inclination of this concave inclined area 42 is greater than the inclination of the thread axis with respect to the axis X. In particular, the angle which the concave inclined area 42 makes with the axis X lies in the range between 5 ° and 15 °, for example in the order of 7.125 ° (taper 1/4). Preferably, the inclination of the concave inclined region 42 is selected so as to be substantially the same as the inclination of the convex inclined region 41. For the same inclination, the variation of the inclination along these inclined areas is acceptable as long as at any position the tangent forms an angle with the rotation axis smaller than 80 ° (preferably smaller than 70 °).

The initial portion PT2 extends parallel to the axis X along the axial distance d2 between the inboard abutment EI and the threaded connection portion PC 2. The axial distance d2 may be in the range of 5mm to 50 mm.

Preferably, the annular portion 45 has a large radius of curvature. The annular portion 45 projects towards the inside of the tube and is intended to come into interfering contact with the projecting inclined area 41, so that the seal is locally ensured by radial interference.

The radius of curvature of the annular portion 45 is between 50mm and 800mm (for example of the order of 300 mm) in order to distribute the interference pressure as much as possible and avoid local plasticization of the convex tilting zone 41.

When forming the connection 30 of the present invention, the apex 46 of the annular portion 45 defines the desired maximum radial interference position between the terminal portion (PT1) and the initial portion (PT 2). The apex 46 is defined at a distance d5 parallel to the axis X of the inboard shoulder EI.

The tip 46 of the annular portion 45 defines an axial distance d5 which is substantially equal to the axial distance of the pressing position of this tip of the annular portion 45 of the convex inclined region 41 with respect to the internal abutment BI.

This distance d5 defines the position of maximum radial interference obtained between the connecting element 11 and the connecting element 13 with respect to the inboard abutment. The distance d5 ranges, for example, between 5mm and 25mm, preferably between 10mm and 20mm, for example, in the order of 18 mm. The distance d5 is greater than a minimum value defined by one-half of the distance d1 and one-half of the distance d 2.

d5> min (50% of d 1; 50% of d2)

Preferably, the first and second electrodes are formed of a metal,

d5> min (70% of d 1; 70% of d2)

In all cases, d5 is less than d3 and less than d 2.

For example, the axial distance d5 lies in the range of 60% to 90%, in particular 70% to 80%, of the axial distance d2 of the starting portion PT2 relative to the inner shoulder.

For example, the axial distance d5 lies in the range 60% to 90% of the axial distance d1 of the end portion PT1 relative to the inner abutment, in particular in the range 70% to 80% of this distance d 1.

Thus, the maximum interference surface 46 is arranged at a distance from the inboard abutment BI in order to prevent the inboard abutment from being damaged and irregularly shaped when forming the seal. Such spacing also means that during coupling of the male element within the female element until the connection 30 is made, a guiding function along the inner abutment is provided, without the risk of damaging the sealing area. Another advantage of this location back from the maximum sealing surface 46 is that wear during coupling is limited and the stress peaks at the end of the fit are limited.

Fig. 7 shows the variation of the deformation determined by the finite element method calculation during the assembly of the connection 30 along the axis a of the diagram, measured as a% of the elastic deformation along the axis B.

At the start of the assembly, the maximum radial interference provided in the inboard abutment BI, the outboard abutment BE and the connection is not deformed for a certain number of turns over the duration of the phase t 1. Next, during a stage t2, a radial interference is progressively formed between the tip 46 of the annular portion 45 and the convex inclined region 41 as the assembly progresses. Fig. 8a shows the connection being made at the beginning of stage t 2. It can be seen that for the connection 30, during this phase t2, the deformation at this interference region is very slow and gradually rises. Fig. 8b shows the connection towards the end of the phase t 2.

Finally, in the final part of the assembly, stage t3 aims at bringing the abutments into contact; the outer abutments are brought into contact first and then the inner abutments are brought into contact. Stage t3 is terminated by reaching a predetermined make-up torque for connection 30. The particular configuration of the terminal part PT1 and the initial part PT2 means that the maximum interference zone 46 can be maintained at a deformation degree always less than 100% of its yield strength. Fig. 8c shows the connection at the end of stage t 3.

This particular configuration means that wear can be avoided during the formation of the connection 30.

The connection 30 of the present invention has the advantage of passing the following tests: during its entire use, under conditions of 20000psi internal pressure and 15000psi external pressure, assembly and disassembly were continued 100 times and sealing was ensured at the same time.

In practice, the seal is verified according to ISO standard ISO-13628. At diameter TJ_ODA gas-tight seal with an internal pressure of 30000psi was also demonstrated with a 13.02cm (51/8 inches) joint.

Using finite element modeling testing, it has also been demonstrated that the connection 30 of the present invention is capable of sealing for pressure loads in excess of 200Mpa (e.g., in excess of 400Mpa or even 600 Mpa).

In the practice according to the invention, the connection 30 according to the invention satisfies the criteria set forth by the two conditions defined below:

(1) the ratio is the radius of the annular portion 45 (in mm)/the maximum radial interference measured at the diameter (in mm).

The maximum radial interference measured at the diameter corresponds to twice the value imax shown in fig. 8c, which represents the maximum radial interference measured at the radius.

(2) Ratio > -0.261 × [ steel grade (Mpa) of the second body 10 ] +400

By way of example, when the second body 10 is made of a steel of the 130ksi grade (i.e. 896Mpa), the dimensions of the second body are then chosen, for example, so that the radius of curvature of its annular portion 45 is 300mm and the maximum radial interference at the diameter is 0.41 mm.

Advantageously, the maximum radial interference 46 is located at a radial distance e with respect to the start of the threaded portion when the connection 30 is made, so as not to affect the load already applied in the threaded portion. The radial distance e lies, for example, in the range from 2mm to 5mm (for example, in the order of 3.12 mm).

Advantageously, as shown in fig. 8b and 8c, the convex inclined zones 41 and the corresponding concave inclined zones 42 are provided so that they also form a radial interference. In particular, the value of the interference i between these

inclined areas

41 and 42 is less than the maximum radial interference imax. As an example, the constant interference i is for example less than 2/3 of imax, or even less than half of imax, over the whole part of the

areas

41 and 42 in interference contact, since the inclination is the same. Thus, the interference region extends over the entire axial distance d 5. Preferably, when the connection 30 is made, the interference obtained between the second body 10 and the third body 12 extends continuously from the rounded portion 43 to the position of this maximum radial interference 46, or even slightly beyond the maximum radial interference 46 in the direction of the connection portion.

On the terminal portion PT1, the male tilting zone 41 is connected to the cylindrical portion 48 via a fillet radius 47, the diameter of said cylindrical portion 48 being strictly smaller than the diameter observed in the thread root of the male threaded connection portion PC1 immediately adjacent to the terminal portion PT 1. Alternatively, the rounded corners 47 may be acute and non-circular. The cylindrical portion 48 is connected via a fillet radius 49 to an inclined fillet portion 50, which inclined fillet portion 50 provides a connection with a male threaded connection PC 1.

Reference diameter D at tip 46₄₆Smaller than the reference diameter D of the cylindrical portion 48₄₈. In particular, the two reference diameters D₄₆And D₄₈The difference between is in the range of 0.5mm to 1mm (e.g. of the order of 0.81 mm).

On the starting portion PT2, the annular portion 45 is connected to the inclined rounded portion 52 via a convex rounded radius 51. The inclined radiused portion 52 connects to the cylindrical portion 54 via a radiused radius 53, the cylindrical portion 54 providing a connection with a female threaded connection PC 2.

The axial distance d4 defines the axial distance along the axis X, which is the sum of the axial distances along the axis X of the recessed inclined area 42 and the annular portion 45. The distance d4 represents more than 50%, more preferably more than 70% of the axial length d 2. In practice, d4 is greater than d5 since annular portion 45 extends on either side of its apex 46. In practice, the annular portion is designed so that its tip 46 is not centered in the middle of said annular portion 45. The annular portion 45 includes a portion 61 between the tip 46 and a fillet 62 connecting to the concave angled region 42, the portion 61 extending an axial distance greater than an axial distance of a second portion 60, the second portion 60 defined between the tip 46 and the convex fillet radius 51. The fillet 62 is for example designed to tangentially connect to the annular portion 45 and the concave tilting zone 42.

Throughout this specification, unless stated otherwise, the term "comprising" should be understood as "comprising at least one".

Claims

1. A threaded connection (30) with double abutment shoulders comprising a first tubular component and a second tubular component, the first tubular component being fitted on the second tubular component, the first and second tubular components being intended for exploration or operation of hydrocarbon wells;

-the first substantially cylindrical tubular component (C1) has an axis of rotation (X) and comprises a protruding end comprising an outer abutment (BE), a protruding threaded connection portion (PC1) extending via an unthreaded terminal portion (PT1) defining an inner abutment (BI) at an axial end thereof, an unthreaded protruding base defined between the outer abutment and the protruding threaded connection portion;

-the second substantially cylindrical tubular part (C2) comprises a female end defining at a free end a bearing Surface (SA) which is pressed against the external abutment, this female end having on its inner surface a female threaded connection portion (PC2) which is made up with the male threaded connection portion and ending in an internal shoulder (EI) which is pressed against the internal abutment, an unthreaded start portion (PT2) connecting the female threaded connection portion to the internal shoulder, an unthreaded female base (B2) being defined between the female threaded connection portion and the bearing surface,

characterized in that said threaded connection comprises a maximum radial interference forming locally a sealing surface, between said male threaded connection portion and said inner or outer abutment, this maximum radial interference being located at a non-zero distance (d5) from said inner and outer abutments respectively, this distance being at least greater than 50% of the minimum between the axial distance (d1) of said terminal portion and the axial distance (d2) of said starting portion.

2. The connection of claim 1, wherein the maximum radial interference is between the male threaded connection portion and the inboard abutment.

3. A connection according to claim 1 or 2, characterized in that a continuous interference is formed from the inner abutment to the maximum radial interference.

4. Connection according to claim 1, characterized in that the maximum radial interference is obtained by the interaction between the tip (46) of an annular portion (45) located on one of said terminal portion or said initial portion and a tapered portion located on the other of said terminal portion or said initial portion.

5. The connection according to claim 4, characterized in that the annular portion (45) is located on the initial portion (PT2) and the tapered portion is located on a convex inclined area (41) of the terminal portion (PT 1).

6. A connection according to claim 4 or 5, wherein the radius of curvature of the annular portion is greater than 50 mm.

7. A connection according to claim 6, characterised in that the radius of curvature of the annular portion is of the order of 300 mm.

8. The connection according to claim 4, characterized in that the tip (46) of the annular portion is located at an axial distance (d5) with respect to the internal abutment (BI) which is in the range between 60% and 90% of the axial distance (d2) of the initial portion with respect to the internal shoulder.

9. The connection according to claim 8, characterized in that the axial distance (d5) of the tip (46) of the annular portion with respect to the inner abutment (BI) is situated between 70% and 80% of the axial distance (d2) of the initial portion with respect to the inner shoulder.

10. The connection according to claim 4, characterized in that the position of the compression of the tip (46) of the annular portion on the convex inclined area (41) of the terminal portion is located at an axial distance (d5) with respect to the inner abutment, said axial distance lying between the range 5mm and 25 mm.

11. A connection according to claim 10, characterized in that the position of the compression of the tip (46) of the annular portion on the convex inclined area (41) of the terminal portion is located at an axial distance (d5) with respect to the inner abutment, said axial distance lying in the range 10mm to 20 mm.

12. A connection according to claim 10, characterized in that the position of the compression of the tip (46) of the annular portion on the convex inclined area (41) is located at an axial distance (d5) of 18mm with respect to the inner abutment.

13. A connection according to claim 4, characterized in that the maximum radial interference is located at a radial distance (e) from the starting point of the threaded connection.

14. A connection according to claim 13, characterized in that the radial distance (e) of the maximum radial interference from the starting point of the threaded connection is in the range 2mm to 5 mm.

15. The connection according to claim 1, characterized in that the thread inclination (Y) of the respective male and female threaded connection portions with respect to the axis of the threaded connection is situated in the range between 8.33cm/m (1.0 inch/foot) and 10cm/m (1.2 inch/foot).

16. A method for coupling the threaded connections of any of claims 1-15, wherein the threaded connections develop a nominal makeup torque greater than 22250N/m when the threaded connections have an outside diameter greater than 13.02cm (51/8 inches) and an inside diameter greater than 7.18cm (27/8 inches).

17. A method for coupling the threaded connection according to any one of claims 1-15, wherein the threaded connection develops a nominal makeup torque greater than 70000N/m when the threaded connection has an outer diameter greater than 20.32cm (8 inches) and an inner diameter greater than 13cm (5.119 inches).